1. Field of the Invention
The present invention generally relates to geometrical instruments for determining levelness and ninety degree corners. More particularly, this invention relates to a combination level and square for use by craftsmen.
2. Descriptiom of the Related Art
Craftsmen such as carpenters, plumbers, electricians, and contractors, for example, repeatedly make use of several basic tools in their jobs. Some of the most commonly used tools include scales, squares, levels, straight edges, among others.
There have been numerous attempts in the past to combine several of these commonly used tools into one for convenience. For example, U.S. Pat. No. 732,827, issued to Chambers, discloses a hinged level whose two parts can move in the plane of the level so as to be oriented with respect to each other at angles from 0 to 90 degrees. See FIG. 1.
U.S. Pat. No. 1,210,370, issued to Dvorak, discloses a combination level and square which incorporates an alternative hinge that also allows the two parts of such a level to be oriented with respect to each other at angles from 0 to 90 degrees. See FIG. 2.
U.S. Pat. No. 4,317,289, issued to Conn, and U.S. Pat. No. 5,459,935, issued to Paulson, disclose similar such combinations of a level and a square. See FIGS. 3 and 4.
Meanwhile, U.S. Pat. No. 4,481,720, issued to Sury, discloses a combined level and protractor in which the level vials can be recalibrated. A protractor arm pivots from a recess within the main body to a 90 degree position. A stop structure including a thumb wheel and a lead screw shaft can be used to fix the angular position of the protractor arm.
Other prior patents showing multiple-section tools which may be used as levels or squares include U.S. Pat. Nos. 120,675, 339,287, 1,014,402, 1,806,396, 2,559,961, 2,728,989, 2,878,569, and 3,783,518.
All of these combination tools seem to share two common traits: (a) the two movable parts of the tool are hinged in such a manner that their motion is in the same plane (e.g., the x-y plane shown in FIG. 2) as that which is defined by the plane of use of the tool; the manner of hinging of these parts does not allow for motion outside of the such tool""s intended plane of use (i.e., there is no motion in the z-plane of FIG. 2), and (b) the hinging of the two parts is such that they may be oriented with respect to each other at any angle between 0 to 90 degrees. These traits prove to be important is considering the novelty of the present invention.
Despite a long recognized need for a tool that offers the combined functions of a level and a square, and despite considerable prior art directed towards such a combination tool, such a tool has not yet accepted for wide spread use in the construction industry. Accordingly, there remains a need for an improved device combining both the functions of a level and a square.
There has been summarized above, rather broadly, the prior art that is related to the present invention in order that the context of the present invention may be better understood and appreciated. In this regard, it is instructive to also consider the objects and advantages of the present invention.
An object of the present invention is to provide an improved, combination level and square that will overcome the user problems which have prevented the wide spread use of such devices in the construction industry.
Another object of the present invention is to provide an improved, combination level and square that has a more durable and reliable joint than the simple hinge joint which has been used in all prior art version of such devices.
A still other object of the present invention is to provide an improved, combination level and square that is easy to use and can withstand the sometimes extreme physical demands made on it by workers in the construction industry.
A further object of the present invention is to provide an improved, combination level and square that is constructed so as to continue to function properly and accurately, despite weather conditions and general wear and tear.
Another object of the present invention is to provide an improved, combination level and square whose hinging mechanism can resist the twisting and bending moments applied to the tool during mishandling and transport.
A still further object of the present invention is to provide an improved, combination level and square whose accuracy is maintained despite constant wear and tear on its components.
Another object of the present invention is to provide an improved, combination level and square in which the level may be quickly and easily turned to or returned from the 90 degree square position to the aligned position simply by a quick movement by the hand of the user and without the release of any extensive fasteners, locking devices, etc.
Other objects and advantages of the present invention will become readily apparent as the invention is better understood by reference to the accompanying drawings and the detailed description that follows.
The present invention is generally directed to satisfying the need set forth above and the problems identified with prior craftsman""s tools that function as a combination level and square.
In a preferred embodiment, the present invention takes the form of a combined carpenter""s level and square. It comprises: (a) a first elongated, straight section having distal and proximate ends and a centerline therebetween, with the proximate end having a flat surface whose upper part forms a 45 degree angle with the section""s centerline, (b) a first leveling bubble fixed in this first section, (c) a second elongated, straight section having distal and proximate ends and a centerline therebetween, with the proximate end having a flat surface whose upper part forms a 135 degree angle with the section""s centerline, and with the second section proximate end being proximate the first section proximate end, (d) a second leveling bubble fixed in this second section, (e) a coupling means having a bottom portion that is connected to the first section proximate end and a top portion that is connected to the second section proximate end and a connecting rod that is configured so as to connect these portions and allow them to independently rotate about the rod, the centerline of the rod being perpendicular to both proximate ends and located such that it intersects the section centerlines, and (f) a ball detent fixed in one of the proximate ends of the straight sections.
This tool is characterized by the fact that its second section has one of two fixed orientations with respect to its first section. When in its first position, the centerlines of the sections are aligned with each other so that their outer surfaces form straight lines. Meanwhile, when the second section has been rotated 180 degrees about the tool""s connecting rod the tool assumes its second position, the centerlines of the sections then form a ninety degree angle with one another so that the tool may be used as a square.
Other embodiments of the present invention may become readily apparent as the invention is better understood by reference to the accompanying drawings and the detailed description that follows.